title: Susceptibility of tick cell lines to infection with Alkhumra haemorrhagic fever virus.
abstract: BACKGROUND
  Although Alkhumra haemorrhagic fever virus (AHFV) has been isolated from ticks, epidemiological data suggest that it is transmitted from livestock to humans by direct contact with animals or by mosquito bites, but not by ticks. This study was carried out to assess the ability of the virus to replicate in tick cells in vitro.
  
  
  METHODS
  AHFV was inoculated into cell lines derived from the hard ticks Hyalomma anatolicum (HAE/CTVM9) and Rhipicephalus appendiculatus (RAE/CTVM1) and the soft tick Ornithodoros moubata (OME/CTVM24). Inoculated cells were directly examined every week for 4 weeks by real-time reverse transcription PCR and by IFAT using polyclonal antibodies.
  
  
  RESULTS
  AHFV RNA was detected in all three inoculated tick cell lines throughout the 4-week observation period at levels up to almost twice that of the inoculum, but none of them exhibited a cytopathic effect. AHFV antigen could be detected in all three cell lines by IFAT. Titration of tick cell culture suspension in LLC-MK2 cells yielded AHFV titres of 10(6.6) 50% tissue culture infective dose (TCID50)/ml for OME/CTVM24 and 10(5.5) TCID50/ml for RAE/CTVM1 cells after 4 weeks of culturing; no viable virus was detected in HAE/CTVM9 cells.
  
  
  CONCLUSIONS
  This is the first description of propagation of AHFV in tick cells.
authors.affiliation: Department of Medicine, Faculty of Medicine, King Abdulaziz University, P.O. Box 80215, Jeddah 21589, Saudi Arabia.
authors.forename: Tariq A
authors.initials: TA
authors.lastname: Madani
authors.forename: El-Tayeb M E
authors.initials: el-TM
authors.lastname: Abuelzein
authors.forename: Lesley
authors.initials: L
authors.lastname: Bell-Sakyi
authors.forename: Esam I
authors.initials: EI
authors.lastname: Azhar
authors.forename: Hussein M S
authors.initials: HM
authors.lastname: Al-Bar
authors.forename: Huda
authors.initials: H
authors.lastname: Abu-Araki
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Hassan
authors.forename: Badr E
authors.initials: BE
authors.lastname: Masri
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Ksiazek
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004198:Disease Susceptibility; D019084:Fluorescent Antibody Technique, Indirect; D003225:Hemorrhagic Fever Virus, Crimean-Congo / Q000254:growth & development*; D006479:Hemorrhagic Fever, Crimean / Q000453:epidemiology; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D013987:Ticks / Q000166:cytology / Q000821:virology*; D014779:Virus Replication
keywords: Alkhumra haemorrhagic fever virus; IFAT; Indirect fluorescent antibody test; Propagation; Real time RT-PCR; Tick cell lines